Travel working machines such as combines and tractors with a function of automatically traveling without being operated by a driver have been proposed. For example, Patent Literature 1 discloses a travel working machine including a mode switching means for switching modes between an automatic travel mode that allows the machine body to automatically travel along a target travel route set in advance, a manual travel mode that allows the machine body to travel in response to manual operation, an automatic travel preparation mode, and a manual travel preparation mode. The automatic travel preparation mode is a mode of transition from the manual travel mode to the automatic travel mode, and, in this mode, the engine changes to idling speed and enters a travel stoppage state, and the machine body waits until an automatic travel start instruction is issued. When data necessary for automatic travel in the automatic travel preparation mode is obtained and an automatic travel start instruction is issued, the mode changes to the automatic travel mode. Furthermore, in the automatic travel preparation mode, if automatic travel suspension conditions are satisfied or a predetermined period of time has elapsed after the transition, the mode changes to the manual travel preparation mode. The manual travel preparation mode is a mode of transition from the automatic travel mode to the manual travel mode, and, in this mode, the engine changes to idling speed and enters a travel stoppage state.